Peterson, R. (1997). Pigskin: The early years of pro football. Oxford University Press.
Chicago-čujuhus (17. p.)Peterson, Robert. Pigskin: The Early Years of Pro Football. New York: Oxford University Press, 1997.
MLA-čujuhus (9. p.)Peterson, Robert. Pigskin: The Early Years of Pro Football. Oxford University Press, 1997.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.